1. Field of the Invention
The present invention relates to chip-type electronic components, and more particularly, relates to a chip-type electronic component comprising a ceramic body and to a manufacturing method therefor.
2. Description of the Related Art
Various electronic components including such as laminated ceramic capacitors have been formed into chip-type components in order to reduce the mounting area on a circuit board and making a size of the circuit board smaller. However, since the surface of the ceramic for use in the electronic components is exposed to the outside, the reliability in terms of humidity resistance and the like has not been satisfactory. Accordingly, a technique to realize superior reliability is disclosed in Japanese Unexamined Patent Application Publication No. 3-250603 in which the surface of a ceramic exposed to the outside is covered by a glass coating layer.
However, generation of cracks is likely to occur in the glass coating layer in the chip-type ceramic electronic component described above, and hence, degradation of the insulating resistance or the like occurs in the ceramic body.
Accordingly, an object of the present invention is to provide a chip-type electronic component in which generation of cracks in the glass coating layer is unlikely to occur, and hence, degradation of the insulating resistance in the ceramic body is unlikely to occur. In addition, the present invention also provides a manufacturing method therefor.
To these ends, a chip-type electronic component of the present invention comprises a ceramic body and a glass coating layer provided on the body, wherein the composition ratio of alkaline element(s) to the silicon element in the glass coating layer is gradually increased from the vicinity of the surface of the glass coating layer to the inside thereof. In this connection, the vicinity of the surface means the border defined by the place at which the influence of moisture and carbon dioxide in the air adsorbed on the surface of the glass coating layer disappears.
In the chip-type electronic component having the structure described above, since the atomic ratio of the alkaline metal content to the silicon content in the glass coating layer is gradually increased from the vicinity of the surface of the glass coating layer to the inside thereof, generation of cracks is unlikely to occur in the glass coating layer and degradation of the insulating resistance in the ceramic body is also unlikely to occur.
The ceramic electronic component described above can be obtained by a step of forming a glass coating layer on a surface of a body comprising a ceramic, in which the atomic ratio of the alkali metal content to the silicon content in the glass coating layer is about 0.3 or more; and a step of dipping the body provide with the glass coating layer in an acidic aqueous solution.